This Invention Patent application belongs to the field of equipment and devices used in association with conveyor belts, which may be used in various bulk transportation activities.
This Invention Patent application provides an automatic device for integrating conveyor belt scales, which brings safety and efficiency to calibration operation of scales mounted to conveyor belts, while avoiding unnecessary risks to people. The device object of this patent application applies to mounted-type integrating conveyor belt scales, mounted to bulk material conveyors, featuring a structure that supports racks with rolled cylinders, which, when assembled, are able to support the conveyor belt.
Integrating Conveyor Belt Scales require periodic calibration to ensure that measurements are within the tolerance thresholds for the service precision class, according to metrological requirements.
Standard calibration processes require complete stoppage of the respective conveyor, for manual input of standard weights in the form of independent masses, or streams of pre-measured masses of same length.
Devices that apply standard weights through various indirect mechanisms are present in the market; however, they must be manually activated and require the operator to be near the conveyor bed.
In addition to the aforementioned devices included in the state of the art, there is also U.S. Pat. No. 6,818,841 B1 of Nov. 16, 2004, which provides calibration through a computer-controlled weight input onto a conveyor line, without interruption of conveyor operation, and BRPI 0802249-6 (A2) of Aug. 4, 2009.
Manual calibration operation using standard weights presents risk to those performing the task, due to the fact that integrating scales are often installed in high places with limited protection, or unhealthy locations, and require handling of significant amounts of weight.
Even when the integrating scale is placed in a suitable location, there is serious risk of accident if the conveyor is moving, intentionally or otherwise.
When conveyor operators are required to be near the integrating scale, equipment stoppage may be requested due to occupational safety requirements.
Regarding U.S. Pat. No. 6,818,841 B1, it is found that the described object is subject to limitations which degrade the exactness of obtained calibrations, due to the fact that the load measurement mechanism is supported by joints with rollers, or fulcrums, or other bearings, and also due to part of the reaction to the weight force that acts upon the measurement rolls is exerted by the joints, and the rest is applied to the sensor, which may be a load cell or other type of force transducer.
Said mechanism features a limitation, which is that the attrition to the joints negatively affects the accuracy of the calibration process, as well as the weighing process itself.
One cannot assume that the reaction component is cancelled due to attrition, between calibration and use, as this attrition phenomenon is characterized by: non-repeatability, hysteresis, instabilities resulting from contamination, corrosion, variations in temperature, which may differ from the moment of calibration and weighing during operation.